Mass and heat transfer analysis in fructose concentration by osmotic distillation process using hollow fibre module

Abstract

Osmotic distillation process was carried out on a hollow fibre membrane module using fructose solutions and clarified grape juice as feeds. The influence of operating parameters such as feed and brine flow velocities, feed concentration, and temperature, on the osmotic distillation flux was studied. For the experimental conditions employed, the water flux varied from 0.58 kg m −2 h −1 to 2.02 kg m −2 h −1. Temperature and feed concentration had significant effect on flux. On the contrary, feed and brine velocities had little effect on flux. The increase of feed and brine velocities or change of the hydrodynamic conditions also enhanced flux. The concentration polarization at high flow velocities can be neglected. In this work, the value of temperature polarization was small and the polarization coefficient Θ was estimated. It was found that temperature polarization reduced the driving force for mass transfer approximately 5–6%. However, this phenomenon affected the transport resistance of the system. The concentration and temperature polarization can be reduced by operating the process at high Reynolds number and low temperature. The transport resistance was affected by changing of operating condition such as feed velocity and temperature. The major transport resistance of the process was in the membrane.